MCSO: DNA evidence used to solve 1988 homicide

Using new DNA technology to solve a nearly 25-year-old Fort Bragg murder case, local authorities and the state Department of Justice determined last week that the brother-in-law of Georgina Pacheco, 20, killed her in 1988 and himself about 10 years later, the Mendocino County Sheriff's Office announced Tuesday.

"We of course offer our condolences to the family, because this is a two-way loss," Mendocino County Sheriff Tom Allman said. "Not only did they lose a family member, but was determined that she was murdered by another family member."

Pacheco's body was found apparently dumped in thick brush, naked except for one shoe, by a man walking his dog on Pearl Ranch Road Sept. 10, 1988. Authorities found an orange and black nylon rope -- the kind typically used in commercial fishing -- tied around her neck "in an intricate knot" resembling a fishing knot, MCSO Detective Sgt. Jason Caudillo said at a press conference held to announce the case's closure.

Robert James Parks, 27, a self-employed commercial fisherman, had picked her up from the Sea Pal Restaurant in Fort Bragg, where she worked, on Sept. 1, and was the last person to see her alive, according to Lt. D.J. Miller, who worked on the case daily for the two years following the incident. She didn't show up at a local hangout and was reported missing three days later.

Parks was one of many suspects at the outset of the investigation, according to MCSO detective Andrew Porter, who took over the cold case in 2009, but wasn't the main suspect until the last year.

"Initially our focus was on him, especially since he was the last person to see Georgina alive," Miller said. "We did an extensive investigation at that time involving him, including ... a polygraph examination, which he passed."

Without any other usable evidence, detectives at the time worked on other leads. According to Porter, Parks gave investigators information pointing to other suspects.

An autopsy revealed Pacheco died of strangulation and blunt force trauma to the head, apparently from a tire iron or abalone pry bar, according to the MCSO.

Parks was found dead in his fishing boat after he called family members July 21, 1998 and told them he was going to commit suicide by sinking the boat, according to the MCSO.

"I heard different things -- that he shot holes in the bottom of it, to he pulled a plug -- I'm not sure exactly," Porter said. "I do know also that he somehow tied or fastened himself to the boat."

He speculated that Parks' motive was remorse for Pacheco's death.

The motive for the murder isn't known, according to the MCSO.

"It's up in the air," Miller said. "I can only speculate that it may have been sexually related."

Vaginal swabs collected at the time were analyzed by the Federal Bureau of Investigation, which found nothing useful, according to DOJ Senior Criminalist Meghan Mannion-Gray, who spoke at the conference.

Clippings from Pacheco's fingernails and vaginal swabs taken as part of a sexual assault investigation at the time revealed a blood type, but the technology used to identify people based on DNA evidence didn't exist until 2000, when MCSO detective Kevin Bailey submitted the some of the evidence to the state DOJ's DNA laboratory.

A backlog at the time meant results weren't available until 2005, according to the MCSO. Even then, the laboratory found only that the DNA from Pacheco's autopsy was male sperm. There was enough to exclude suspects, but not enough to run through the Combined DNA Index System to identify a suspect, according to the MCSO.

"Back then (for) the type of technology, you needed very large quantities of DNA and very complete DNA," Mannion-Gray said. "Now we can use much smaller quantities, and even if the DNA is damaged, our technology still allows us to analyze it."

What remained of the vaginal swabs were re-examined in the past year, according to Mannion-Gray, when she found enough DNA on the wooden sticks to which the cotton swabs had been attached to show her male sperm under a slide and to help her construct a compete DNA profile.

The DNA was compared to that of Parks' daughter and the girl's mother, and Parks was identified as the sperm donor, according to Mannion-Gray.

She said the process isn't what's typically referred to as "DNA familia searching," but described it as a "kinship" process "similar to what is done (after) a mass disaster and you're trying to identify remains using family members."

The DNA profile Mannion-Gray developed from the swab stick matched a partial profile from the swabs of Pacheco's hands and her fingernail clippings, according to the MCSO.

"We don't use the word definitive;' it's not a very scientific term for us," she said. "We just say it's strong evidence. We've got statistical likelihoods for that ... so it would be what we would call strong evidence in court."

The DOJ used the DNA evidence to determine that it was between 190,000 and 250,000 times more likely that the DNA found on the victim belonged to Parks than to anyone else, according to Mannion-Gray.

The Sheriff's Office has in its files about 20 unsolved homicide cases dating back to the 1960s, according to Caudillo, who has been with the office 13 years. Pacheco's murder was the third homicide in the last 10 years to be solved using DNA evidence, he said, and the first to be solved using familial DNA evidence.

Tiffany Revelle can be reached at udjtr@ukiahdj.com, on Twitter @TiffanyRevelle or at 468-3523.